Brake



Feb. 27, 1940. R. A. GOEPFRICH BRAKE Filed May 22, 1937 3 Sheets-Sheet 1 INVENTOR,

@0001. PH 67. GOEPFP/CH ATTORNEY.

Feb. 27, 1940.

R. A. GOEPFRICH v BRAKE Filed May 22, 1937 3 Sheets-Shee't 2 1N VENTOR. Gazpremw Feb. 27, 1940.

R. A. GOEPFRICH BRAKE Filed May 22. 1937 s sheets-sheet s &

N I v INVENTOR E00 04 PH GOFPFP/Ch' ATTORNEY.

Patented Feb. 27, 1940 PATENT OFFlCE BRAKE Rudolph A..Goepfrich, South Bend, Ind.,' assignorto Bendix Products Corporation, South Bend,

Ind., a corporation of Indiana Application May 22 1937, Serial No. 144,117

2 Claims.

This invention relates to fluid pressure braking 7 systems.

An object of the invention is to provide a duplex fluid pressure braking system for motor 6 vehicles, one for actuating the brakes associated with the front wheels of I a vehicle and another for actuating the'brakes associated with the rear wheels of the vehicle. An objectv of the invention is to provide a, fluid pressure braking system for motor vehicles including two separate system's having a single operating means.

Another object of the invention is to provide a fluid pressure braking .system for motor vehicles including two independent systems coupled for concomitant operation with perfect equalization between the systems, or a varied ratio of effectiveness between the systems.

Other objects and advantages of the invention will appear from the following description taken pressure producing device substantially on line- 3-3, Fig. 2;

Fig. 4 is a sectional view substantially on line 4--4, Hg. 2;

' v1Fig. 5 is a side elevation of the adjusting de- Fig. 6 is an end elevation ofJhe adjusting device; and

Fig. 7 is a longitudinal sectional view showing another typeof duplex fluid pressure producing device similar to that shown in Fig. 2 but varying o in details therefrom.

Referring to the drawings for more specific details of the invention, Ill represents a fluid reservoir having a drain opening normally closed by a plug l2 and a filling opening also normally 5 closed by a plug l4 having openings It for venting the reservoir to the atmosphere.

A pair of corresponding oppositely disposed cylinders II and 2| are arranged in spaced relation to one another in the bottom of the reservoir,

and the cylinders open directly into the reservoir.

The cylinder II has a port 22, providing a communication between the cylinder and the reservoir, and a head 24 provided with a discharge port 2' controlled as by a two-way valve 28.

u correspondingly. the cylinder 20 has a port 34;

providing a communication'between the cylinder and the reservoir, and a. head 32 provided with a discharge port 34 controlled as by a two-way valve 36.

A fluid pressure delivery pipe or conduit 38 5 suitably secured to the head 24 in direct communication with the discharge port 26 has branches 4!! and 42 connected respectively to fluid pressure actuated motors 44. correspondingly, a fluid pressure delivery pipe or conduit 46 has 10 branches 48 and 50 connected respectively to fluid pressure actuated motors 52. The fluid pressure actuated motors 44 and 52 are arranged in pairs, one pair for actuating thev brakes associated with the front wheels of the vehicle and another pair 15' for actuating the brakes associated with the rear wheels of the vehicle.

The brakes are preferably of conventional type each including a fixed support or backing plate 54 adapted to be secured to an axle or to an axle 20 housing, a rotatable drum 56 associated with the backing plate and adapted to be secured to a wheel, corresponding interchangeable friction elements or shoes 58 pivoted on the backing plate, and a motor corresponding to the motors 44 and 26 52 mounted on the backing plate between the friction elements or shoes and operative to move the shoes into engagement with the drum against the resistance of a retractile spring 60 connecting the shoes.

Pistons 62 andtlreciprocable in-the cylinders i8 and 20 each include a body portion 66 having a head 68 and a connector 10. The head 68 has a circumferential groove 12 adjacent its face and in this groove is fitted a leak-proof washer 88 l4 fordnhibiting'the seepage of fluid past the having a stem 82 slidable in the passage, and

the stem has longitudinal channels 84 providing for uninterrupted flow of fluid through the passage when the valve is open. The valve has on its head an extension 86 terminating in a knob 88, and a leak-proof. washer 90 sleeved on the extension is retained against displacement by the knob. A spring 92 interposed between the two-way valve on the head of the cylinder and the valve 80 normally retains the valves on their to the shaft outside of the reservoir is an arm I00. A sleeve I02 mounted for rotation on the shaft 94 has suitably secured thereon within the reservoir an arm 96 connected as by a link I06 to the connector I0 of the piston 64, and keyed to the sleeve outside of the reservoir is an arm I08.

The arms I00 and I08, keyed to the shaft 94 and to the sleeve I02 respectively, are connected by rods H0 and H2 to the respective ends of a yoke I I4. A screw I I6 suitably mounted between the ends of the yoke has thereon a hand wheel II8 for rotation of the screw, and a short shaft I20 mounted for travel on the screw has pivotally connected thereto a clevis I22 formed integral with a foot pedal lever I24 pivoted on a suitable support I26 and connected by a retractile spring I28 to a fixed support I30.

By adjusting the screw II6 the leverage may be changed to vary the pressure in the respective systems, or to equalize the pressure in the separate systems to the end that the brake structures may be equalized, or the ratio of effectiveness may be varied so that heavy braking may be applied to one set of brakes and relatively light braking to the other set of brakes.

In operation, upon depressing the foot pedal lever I24, force is transmitted from the lever through the screw II 6 to the yoke II4, thence through the links H0 and H2 to the arms I00 and I08 keyed to the shaft 94 and to the sleeve I02, respectively. This movement of the shaft 94 and the sleeve I02 is transmitted through the arms 96 and I04, keyed to the shaft 94 and to the sleeve I02, respectively, and through the links 98 and I06 to the pistons 62 and 64, resulting in movement of the pistons on their compression strokes.

As the pistons 62 and 64 move on their compression strokes, fluid is displaced from the cylinders I8 and 20 past the two-way valves 28 and 30, through the discharge ports 26 and 34 and the fluid pressure delivery pipes or conduits 38 and 46 and their respective branches to the fluid pressure actuated motors 44 and 52, causing actuation of these motors with the resultant movement of the shoes 58 into engagement with the drums 56 against the resistance of the retractile springs 60, so as to effectively retard rotation of the drums.

Upon release of the foot pedal lever I24, the retractile spring I28 becomes effective to return the foot pedal lever to its retracted position. As the foot pedal lever returns to its retracted position, the pistons 62 and 64 are returned to their retracted positions under the influence of the retractile springs 92. The load on the springs 82 may well be such as to materially assist the retractile spring I28 in returning the foot pedal lever to its normal position, or the load on these springs 92 might be only suificient to urge the valves and two-way valves 28 and 36 to their respective seats.

As the pistons return to their retracted posispective pairs of shoes of the brake structure, and should the quantity of fluid received by the cylinders I8 and 20 be in excess of the quantity required to completely fill the cylinders all excess fluid is returned from the respective cylinders to the reservoir by way of the compensating ports 22 and 30. At the end of this operation the respective systems are again at rest and ready for a subsequent operation.

In Fig. 7 there is shown a pressure producing device similar in most respects to that shown in Fig. 2 and corresponding parts are indicated by similar numerals with the addition of 200. Stops 20I and 203 are provided which are arranged to contact with plungers 208 and 2 respectively for insuring that the valves 282 will be mo ed from their seats when the pistons 262 and 264 are returned to their released positions as shown. By this provision for insuring the opening of the valves 282, it is possible to eliminate the valves 28 and 36 and the ports 22 and 30.

Although this invention has been described in connection with certain specific embodiments,

the principles involved are susceptible of numerous other applications that will readily occur to persons skilled in' the art. The invention is, therefore, to be limited only by the scope of the appended claims.

Having thus described the various features of the invention, what I claim as new and desire cylinders, a rockable shaft mounted transversely of the reservoir, linkage connecting the shaft to 10 of the retractile springs 60 connecting the 'reone of the pistons, a sleeve rotatable on the.

shaft, linkage connecting the sleeve to the other piston, a yoke, linkage connecting one end of the yoke to the shaft, linkage connecting the other end of the yoke to the sleeve, a screw mounted for rotation on the yoke, a pintle mounted for travel on the screw, and a foot pedal lever having an arm pivoted on the pintle.

2. A master cylinder device comprising axially aligned cylinders having pistons mounted therein, a shaft between the pistons having a sleeve mounted thereon, connections between the resepctive pistons and the shaft and sleeve, and

means for rocking the shaft and sleeve RUDOLPH A. GOEPFRICH. 

